1. Field of the Invention
The present invention relates to a prefabricated refrigerator, and more particularly, to a prefabricated refrigerator having high insulation efficiency by improving a fixing structure of insulation panels constituting a cabinet of the prefabricated refrigerator.
2. Description of the Background Art
Generally, a prefabricated refrigerator 1 is assembled in such a manner that sandwich panels 10, 20 and 30 having polyurethane foam therein are fixed to one another as shown in FIGS. 1 and 2. In other words, the prefabricated refrigerator 1 includes a bottom panel 10 constituting the base of a cooling space, a sidewall panel 20 constituting the surrounding of the bottom panel 10 to match a groove 10a of the bottom panel 10, a cover panel 30 covering a top portion of the sidewall panel 20, and a cooling mechanism 40 fixed to a top surface of the cover panel 30 to cool the cooling space of the prefabricated refrigerator 1. In this case, each of the panels 10, 20 and 30 is provided with a groove 10a and a protrusion 20a to facilitate assembly with adjacent panels 10, 20 and 30.
A structure of the sidewall panel 20 will be described with reference to FIG. 3. The sidewall panel 20 includes casings 21a and 22a formed of a metal material to prevent the sidewall panel from being damaged by external impact, and insulation portions 21b and 22b foamed inside the casings 21a and 22a by polyurethane foam. The sidewall panel 20 is assembled in such a manner that a protrusion 22c of each of the panels 21 and 22 is fitted to a groove 21c. 
However, if each of the panels 21 and 22 is completely assembled, a contact boundary surface is formed so that surfaces of the casings 21a and 22a formed of a metal material having high heat conductivity coefficient are in contact with each other. Since this boundary surface serves as a path 90 that transfers heat from the outside of the cabinet of the refrigerator to the inside corresponding to the cooling space, a problem occurs in that insulation efficiency is greatly deteriorated even though the panels 21 and 22 is provided with the insulation portions 21b and 22b. 
Accordingly, problems occur in that power consumption of the prefabricated refrigerator increases due to increase of heat conductivity through the contact surface of the casings, and the condition habitable for mold or bacilli is provided due to the dew formed in a gap by the externally transferred heat. Meanwhile, to remove mold or bacilli, a sterilizing material may be filled with the gap between the casings. In this case, another problem occurs in that quality of appearance is deteriorated.